There are optical amplification modules with semiconductor amplifiers. Such an optical amplification module has a package accommodating a semiconductor optical amplifier, a first optical fiber and a second optical fiber optically connected to the semiconductor optical amplifier, and a first connector and a second connector connected to the first optical fiber and the second optical fiber, respectively. A light beam to be inputted to the semiconductor optical amplifier passes through the first connector via the first optical fiber. A light beam outputted from the semiconductor optical amplifier is connected to the second optical fiber via the second connector. Patent Document 1 discloses a technique relating to such the optical amplification module.
[Patent Document 1] Japanese Patent Application Publication No. 2007-298738
When a plurality of such connectors are disposed in series so as to sandwich the package, the dimensions of the optical amplification module increase.